April 2013 was a big month for cocaine busts in the Central American Transit Zone, and U.S. Customs and Border Protection (CBP) was, as usual, in the middle of things. On April 20, for example, a P-3 Orion maritime surveillance program aircraft flown by a CBP Air and Marine crew patrolling the waters off the coast of Panama City, Panama, spotted a speedboat carrying four people, fuel barrels, and multiple packages. The crew notified Panamanian law enforcement, which intercepted the boat and discovered the fuel barrels onboard were filled with cocaine, with a total estimated value of $242 million.

The P-3 was patrolling as part of Operation Martillo, an international anti-trafficking initiative led from the Key West, Fla. headquarters of the multiservice, multiagency Joint Interagency Task Force-South (JIATF-S). Operation Martillo is designed to stop the flow of contraband along Central America’s Pacific and Caribbean coastlines. Since its launch in mid-January of last year, Operation Martillo has resulted in more than 400 arrests, the seizure or disruption of nearly 200 metric tons of cocaine, and the seizure or destruction of more than 140 vessels and aircraft.

CBP is a critical partner in Operation Martillo; it practically invented maritime surveillance in the Caribbean. In 1987, amidst what CBP’s Executive Director for National Air Security Operations, Lothar Eckardt, called the “Miami Vice days,” when drug smugglers were flying cocaine into the United States aboard small aircraft, the U.S. Customs Service established its aerial surveillance program in Corpus Christi, Texas, with a fleet of P-3 Orions outfitted with Airborne Early Warning (AEW) radar systems adapted from Navy aircraft.

“The P-3 was designed to go out and find those airplanes,” said Eckardt, “and then intercept them, follow them back into the country, and shut down that smuggling route. And we were extremely effective. In the early to mid-nineties, airborne cocaine stopped coming into the country.”

The P-3 program promptly built on this success: Another Air Operations Center was established in Jacksonville, Fla., and several aircraft were fitted with electro-optical infrared (EO/IR) sensors like those in the Coast Guard’s long-range surveillance and transport aircraft, the C-130.

Today, four of 14 P-3s flying out of Corpus Christi and Jacksonville are fitted with EO/IR long-range tracking sensors—but software upgrades have made the two surveillance systems interchangeable, said Eckardt. The AEW radar system, originally built for Navy aircraft to scan for larger threats to a carrier group, has been modified to look for smaller targets – aircraft and speedboats or pangas on the water. The CBP’s long-range tracking P-3s, also, have had the EO/IR sensors in their noses supplemented by maritime search radar in their bellies.

“These two airplanes used to work together in what’s called the Double Eagle package,” Eckardt explained, “where the AEW would hang out high and point out all the targets, and the long-range tracker would go low and visually identify all the targets. But now that we’ve invested in this maritime radar, we’ve been able to split the package, saving the taxpayer a lot of money. Now the airplanes don’t have to go out in pairs anymore – they can go out and operate over their own separate area of water. So it’s basically doubled the size of the area we can search with our current fleet, without having to buy extra airplanes.”

CBP’s maritime surveillance is the linchpin of Operation Martillo’s successes – Eckardt estimates that around 99 percent of the operation’s air surveillance is conducted by the agency’s P-3s. The program’s significance hasn’t changed—if anything, P-3 Orion surveillance has become even more important to the anti-trafficking effort – even as smugglers have altered their tactics. Though illegal air routes through the Transit Zone have been virtually shut down for years, smugglers continue to probe for weaknesses in the nation’s defenses, using the surface vessels – and, in recent years, hard-to-spot semi-submersible vessels – to bring drugs and other contraband up along the Central American coastline.

The first self-propelled semi-submersible (SPSS) to be interdicted in the Caribbean was spotted in July of 2012 off the coast of Honduras – and since then, Eckardt estimated, CBP’s P-3 crews have spotted about 90 percent of the SPSSs to be interdicted in the Western Caribbean.

As more semi-submersibles are interdicted by Operation Martillo, it’s hard to anticipate what drug smugglers will think of next – but whatever they decide to use, it’s likely that CBP’s air surveillance program will remain as important to stopping them as it has been for nearly 30 years.

“Drug smugglers are in a business,” Eckardt said. “They change their means, methods and conveyances often. And we’re a reactive force – as they change the way they do business, we react to it and change the way we do things. JIATF South updates its approach every year, to try to keep up.”